That is if the player misses or is limited in practice. A player can participate fully in practice, but still have physical issues that hinder his performance in a game. That is what we are discussing.

Didn't the Jets get in trouble for not reporting Favre's injury, even though he participated in practice & played in all their games?

I believe it is also the reason Belichick fills out such a thorough injury report, since he got his hands slapped for the same thing.